a) Field of the Invention
The present invention relates to a new structure for a printed circuit board insertion slot connector. More specifically, the present invention relates to an improved structure of the printed circuit board slot connector which consists of special designed conducting plates, a printed circuit board securing member, a mother board securing member or a dual-usage securing member.
(b) Description of the Prior Art
The demand for a high-density printed circuit board connector is high nowadays and the physical size of the connector is headed to be more compact. To meet these goals the conducting plates of the connector is getting smaller. This creates some problem in securing the printed circuit board and keeping the conducting plates in place. For example, when a printed circuit board is inserted into the slot connector, the conducting plates of the connector is not firm enough to it and can possibly be pushed downward and deformed. Some of the conventional structure of the conducting plates have arc segments design at the insertion point. This creates a high resistance during insertion and wear out the conducting plates quickly. In addition, the conventional internal conducting plates and the external conducting plates have a symmetrical design structure, the printed circuit board holes for the conducting plates are standard, therefore, the plastic base must have a structure that conforms to the symmetrical structure of the internal and the external conducting plates, the limited spaces thereof and the size of the insertion slot. These lead to an uneven thickness of the plastic base, as is shown in the sole drawing of the prior art. Therefore, it takes longer to fabricate the plastic base. The uneven thickness can also cause a shrinkage and rough finish which affect the physical appearance of the base. It is also hard to control the accuracy of the dimension.
In addition, a conventional slot connector structure uses a design to secure the connector to the mother board in a lateral direction. Therefore, when the connector is guided into the mother board, it often shifts in the longitudinal direction. For this reason it is not easy to guide the connector into the mother board. The mounting is usually not secure after positioning due to the back and forth movement in the longitudinal direction. Moreover, the plastic securing post of the plastic base is easy to break and is hard to control its tightness. Keeping the post too tight makes it hard to insert into the guiding hole of the mother board, and keeping it too loose makes the connector unsecured in the mother board. Also, the portion of the connector exposed to the bottom of the mother board must be able to withstand high temperature during wave soldering. Therefore, the overall base of the connector must use special plastic material which can withstand high temperature. This drives up the cost of the connector and is not efficient and economical.
Moreover, a conventional printed circuit board connector uses its contact pins to grip the inserted printed circuit board. Since the contact pins and the edge of the printed circuit board are usually plated with a thin layer of metal such as copper or gold, the repeated removals and insertions of the printed circuit board induce wears and tears of the connector. Therefore, the gripping of the contact pins on the circuit board shall not be too tight. If the gripping force were too tight, the metal layer on the surface of the contact can be scratched off due to the repeated insertion and removal of the printed circuit board. This degrades the quality of the connector. In general, the thickness of the printed circuit board are not standard, and the conventional connector are usually designed to adapt a thicker printed circuit board. Since the contacts are not allowed to grip the inserted circuit board tightly due to the aforesaid reasons, therefore, when a thinner printed circuit board is inserted into the connector, a gap is left on each side of the connector in the longitudinal direction. As a consequence, the inserted circuit board tends to skew to one side of the connector, causing a scratching on the plastic surface and an unbalanced pressure on the contacts on both sides. These lead to a degrading on the gripping and a deformation of the contacts as well as unstable electrical contacts.